Which describes the expected value:
a: the sum over all outcomes of the value of the outcome times the probability of the outcome
b: the level of confidence that a sample mean accurately represents a population mean
c: the population mean
d: the interval around the sample mean that you expect to contain the population mean

A   :  The sum over all outcomes of the value of the outcome times the probability of the outcome.

Step-by-step explanation:

Explanation:-

Expectation:-Suppose a Random variable X assume the values x_{1} ,x_{2} ...............x_{n} with respective probabilities   p_{1} ,p_{2} ,...........p_{n}.Then the expectation or expected value of X, denoted by E(x) , is defined as the sum of products of different values of x and the corresponding probabilities.

i.e., E(X) = Σ

about 0.75 hours

step-by-step explanation: